Does backing up your library solve this?
Yes.
So would allowing MC to create Sidecar files for movies, which would then store all the tags for the movie that can't be stored in the file itself. Then even if you lost your Libray and had no backups, re-importing the video files into MC would use the tags in the Sidecar files and get the movie identification correct.
Personally, I don't know how KODI or PLEX could do any better job identifying a movie if only the movie name was known, and that name was ambiguous. Maybe they pick the most popular movie that matches, if the API supports that. Maybe they use sources that MC isn't allowed to use as it is a commercial application.
But MC's movie identification from a filename has been very accurate for me, as I include the movie name and year in the filename, as Zxsix mentioned.
When I rename movie files in MC, which I always do using the RM&CF function for all movies, I always use the structure "Movename (Year).ext", so that it will always be identified correctly if I import it again at some time in the future. That may be something else you could consider doing to avoid having to do all that work again, if you lost everything except the video file itself.